Gxt V055-01 Diagnostic Analyzer Manuel d'utilisateur télécharger pdf (Page 17)

TPS Test

O2 Sensor Test

Volt Amp Meter

Zero Amp Probe

Amps are measured by the Inductive Amp Probe.

Battery voltage is measured at the Battery Power Clips.

Auxiliary volts are read with the Auxiliary Meter Lead and

referenced to either Battery Power Clip. Press SELECT

to change the reference between POS and NEG. Large

digits are displayed for enhanced readability. If excessive

alternator ripple is detected a message signal will appear on the display. Press the MESSAGE key to

display the text.

Whenever zeroing of the amp probe is desired, select this

function. A prompt will remind you that the amp probe

should be disconnected. The menu will reappear a few

seconds after a successful zero.

This is a computer aided test to check for glitches in

a position sensor signal. When a position sensor on a

throttle or air ﬂow vane is moved from the rest position

to the top, the output voltage should move just like the

position shaft. A dedicated glitch detector operates

continuously and is not dependent upon sample rate.

Connect the Auxiliary Meter Lead to the throttle position sensor output wire. Switch the ignition key to the

ON position. The test screen will appear with a prompt to move the sensor slowly through its range.

Slowly move the sensor shaft through its full range. Using the voltmeter display, check that the output

responds to a typical range of 1 to 4 volts. If glitches are detected, arrows will appear in place of the

prompt, showing the voltage location of each glitch. Recheck the sensor for intermittent faults near the

indicated problem voltages. The arrows can be cleared by pressing the NEXT key.

Connect at the sensor harness plug or ECM. Do not

penetrate wire insulation where moisture could cause

corrosion or electrical leakage to ground.

Voltage from the vehicle O2 sensor is monitored for

crossings per second through the stoichiometric point

(0.45v), indicating rich and lean conditions. Recent

minimums and maximums are shown and used to

generate a graph. The number of crossings per second

indicates the activity level of the system. When the signal

is active (more than 2 crossings per second), the percent

of time in the rich zone is given.

Typical cross count readings for warm engines running

at a steady fast idle are in the 1 to 3 range. Low rates may indicate a damaged O2 sensor. Multiports

usually cross count fastest, and carbureted engines the slowest.

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Gxt V055-01 Diagnostic Analyzer Manuel d'utilisateur Page 17